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Natural convection flow of a hybrid nanofluid in a square enclosure partially filled with a porous medium using a thermal non-equilibrium model

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journal contribution
posted on 26.03.2020, 14:27 by BM Al-Srayyih, S Gao, SH Hussain
Buoyancy-driven flow inside a superposed enclosure filled with composite porous-hybrid nanofluid layers was investigated numerically using a local thermal nonequilibrium model for the heat transfer between the fluid and the solid phases. The bottom wall of the enclosure was partly heated to provide a heat flux, while the other parts of the wall were thermally insulated. The top and vertical walls of the enclosure were maintained at constant cold temperatures. The Darcy-Brinkman model was adopted to model the flow inside the porous layer. The Galerkin finite element method was used to solve the governing equations using the semi-implicit method for pressure linked equations algorithm. The selected parameters are presented for the Rayleigh number (Ra), 10 3 ≤ Ra ≤ 10 7 , the Darcy number (Da), 10 -7 ≤ Da ≤ 1, the porous layer thickness (S), 0 ≤ S ≤ 1, the modified conductivity ratio (γ), 10 -1 ≤ γ ≤ 10 4 , the interphase heat transfer coefficient (H), 10 -1 ≤ H ≤ 1000, the heat source length (B), 0.2, 0.4, 0.6, 0.8 and 1, and the nanoparticle volume fraction (φ), 0 ≤ φ ≤ 0.2. It has been concluded that the rate of heat transfer of hybrid nanofluid (Cu-Al 2 O 3 /water) is higher than with the pure fluid. Furthermore, at Ra ≤ 10 5 , the heat transfer rate maintains its maximum value when S reaches the critical value (S = 0.3). The values of S, Da, and B were found to have a significant effect on the heat removal from the heat source. Increasing the values of γ and H can strongly enhance the heat transfer rate and satisfy the thermal equilibrium case.


The authors would like to thank the Iraqi Ministry of Higher Education and Scientific Research and the University of Babylon for the financial support to conduct this study. The authors would also like to acknowledge the University of Leicester for providing the necessary resources to carry out this study.



Physics of Fluids, 2019, 31 (4)

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/Organisation/COLLEGE OF SCIENCE AND ENGINEERING/Department of Engineering

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